It’s really no secret that Paul Allen’s sudden leadership on Ebola surprised the heck out of philanthropic community. And us. All summer, we were buzzing about his new wildlife conservation interests, and his commitment to preserving the health of oceans. Oh, okay, we thought, he’s going off in a green direction. Cool. He’s been into environmental conservation for a long time, that makes sense.

But then the Ebola crisis hit, and here came $20 million winging over from Allen, and then another $80 million after that, flying in the face of the fact that he’s a total public health neophyte (just under $2 million committed to public health between 2005 and 2013).

What could explain it? Well, listen up, because we’ve got the goods. As it would happen, Ebola strikes at the intersection of two of Allen’s latest big interests: human health and wildlife conservation.

Sounds crazy, doesn’t it? How could Ebola have anything to do with wildlife conservation? Well, like some other serious viruses that originated in Western Africa (uh, AIDS, for example) Ebola arose over decades of contact between fruit bats, various primate groups, and humans. It’s believed that the virus originated in fruit bats, and was passed to primates via dropped, partially eaten fruit the bats had fed on. Then, through the often vicious business of primates being primates—hunting, defending their territory, eating each other—the virus was passed among chimpanzees, gorillas, macaques, and others. Eventually, it made its way to humans via bush hunters.

Cool story, but what does this have to do with anything? Well, it means that Ebola doesn’t just kill people. It kills apes, too. In 2006, a study published in Science linked the “massive die-off” of gorillas and chimpanzees in the Congo’s Lossi Sanctuary to Ebola. It blamed the virus for 5,000 gorilla deaths—and, lest you forget, gorillas are a species that don’t exactly need a deadly virus stalking their limited numbers, in addition to other dangers such as poachers.

Thankfully, there are organizations working on the “wild” side of Ebola. And in 2009, Paul Allen got in on the game with a $100,000 grant to Kansas State University, which at the time was working on adapting an Ebola vaccine for use on wild apes. In 2011, he was inspired to give again, this time $117,000 to the Wildlife Conservation Society’s mapping project tracking the virus’s reach and lethality in the Congo basin. While it was originally apes that lit Allen’s fire for Ebola, his recent interest in medical research and basic science coordinate nicely with Ebola as well.

Though it’s pretty easy to write off Allen as inexperienced in the public health grantmaking realm, the fact is that his experience making wildlife conservation grants carries over in this instance, as the world tries to save the lives of a few thousand advanced primates in West Africa. Allen himself brings a unique perspective on Ebola that could well prove useful.

Not coincidentally, we named Allen "Philanthropist of the Year" for his leadership on Ebola, along with his growing forays into other areas, most recently cell science.